I wonder if this is William Burton, Bartin and Mary's son, bap 1736
Lincolnshire Chronicle, 9 Feb 1838
Deaths
On the 1st inst, at Bristol, W Bartin Burton, Esq, formerly of Burley, in the County of Rutland, and a Captain in the army, age 73
Baptism (FindMyPast transcript)
4 Sep 1763, Wm son of Mr Wm and Maria Burton, Oakham
However, the "original" (a manuscript transcript) reads -
4 Sep 1763, Wm Bartin son of Mr Wm and Maria Burton.
A William Burton married an Anna Maria Brown, 21 Jan 1762, both of Oakham.
Anna Maria Burton, wife of William Burton, buried 16 Feb 1891, age 51, Burley.
"Mr" is synonymous with "Gent"